Conversion Compression Using The Frequency Offset Mode - Agilent Technologies 8753ET User Manual

Conversion Compression Using the Frequency Offset Mode

Conversion compression is a measure of the maximum RF input signal level where the mixer provides linear
operation. The conversion loss is the ratio of the IF output level to the RF input level. This value remains
constant over a specified input power range. When the input power level exceeds a certain maximum, the
constant ratio between IF and RF power levels will begin to change. The point at which the ratio has
decreased by 1 dB is called the 1 dB compression point. See
Figure 2-27 Conversion Loss and Output Power as a Function of Input Power Level Example
Notice that the IF output power increases linearly with the increasing RF signal, until mixer compression
begins and the mixer saturates.
The following example uses a ratio of mixer output to input power and a marker search function to locate a
mixer's 1 dB compression point.
1. Set the LO source to the desired CW frequency of 600 MHz and power level to 13 dBm.
2. Initialize the analyzer by pressing
3. Set the analyzers LO frequency to match the frequency of the LO source by pressing:
Sweep Setup
SWEEP TYPE MENU
System INSTRUMENT MODE
FREQUENCY: CW
4. To set the analyzer to the desired power sweep range, press:
Power PWR RANGE MAN
10
Start
Stop 10 x1
5. Make the connections, as shown in
Conversion Compression Using the Frequency Offset Mode
.
Preset
POWER SWEEP
FREQ OFFS MENU
800 M/
POWER RANGES
x1
Figure 2-28.
Making Mixer Measurements
Figure 2-27.
Return
LO MENU
RANGE 0
2- 39